VOL. XXVIII NUMBER 5 - World Radio History
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VOL. XXVIII ) ULY , 1 97C NUMBER 5
ii THE SHORT WAVE MAGAZINE July, 1970
THE KW ATLANTA
NOW AVAILABLE WITH REMOTE VFO UNIT
\\\\
N\ Nk\k\ \\\\\
*High power SSB Transceiver *Mobile and fixed station
*Extremely good audio (crystal *Operation on all amateur bands
filters fitted) from 10 to 80 metres
*The Remote VFO Unit available separately if required
Write now for illustrated leaflet containing full technical specification
Purchase ALL your equipment from THE experts
Hy -Gain and Mosley Beams Write for illustrated detailed specifications on other
Vertical Antennas KW Equipment including the KW 2000B ; KW 201 ;
KW Trap Dipoles
Mobile Whips KW 1000 and our list of KW Tested Trade-ins.
Vibroplex Keys
Antenna Rotators
KW Antenna 3 position Switch
KW E -Z Antenna Match Unit
K. W. ELECTRONICS LIMITED
KW PEP Meter
KW Match SWR Indicator ELECTRONICS
1 HEATH STREET,
KW Low -Pass Filters
KW Balun. KW Dummy Load
KW 40 Multipliers
LIMITED DARTFORD, KENT.
All equipment is available TELEPHONE: DARTFORD 25574
on easy terms CABLES: KAYDUBLEW DARTFORDVolume XXVIII THE SHORT WAVE MAGAZINE 257
"LISTEN TO THE WORLD WITH EDDYSTONE"
Eddystone
Your local Eddystone dealer is :
CHESHIRE IRELAND R. T. & I. Electronics Ltd SURREY
Ashville Old Hall
The Transistor Centre John F. MacMahon Ashville Road Home Radio (Components) Ltd
(Wilmslow) Ltd 10, Church Street, Enniskillen, Leytonstone, E.11 240 London Road
Green Lane Co. Fermanagh, N. Ireland Mitcham CR4 3HD
01-539 4986
Wilmslow 24766 Enniskillen 2955 648-8422
Radio Shack Ltd
182 Broadhurst Gardens
ISLE OF WIGHT London, N.W.6 SUSSEX
CORNWALL
01-624 7174 Cosh and Hammond
S.S.B Products Sherratt & Son 29 Beach Road, Littlehampton
7 Little Castle Street 81-82-83 High Street, Newport
Truro Newport 3358-9 Littlehampton 4477 or 4478
MIDDLESEX
Feock 575
KENT
Gurney's Radio Ltd
91 The Broadway, Southall
DERBYSHIRE G. T. & R. Wilson 01-574 2115
WALES
12-14-16 Queen Street
J. & A. Tweedy (Electronic Gravesend
Supplies) Ltd Holt High Fidelity
64 Lordsmill Street Gravesend 63527/8 NORFOLK Picton Arcade, Swansea
Chesterfield Swansea 53254
Percy Powell Radio Ltd The Record Shop
Chesterfield 4982 54 High Street 157 King Street Holt High Fidelity
Tunbridge Wells Great Yarmouth 8 Portland Street, Swansea
Tunbridge Wells 26534 Swansea 41032
DEVON
NORTHUMBERLAND
Graham Newbery LANCASHIRE
(Reg Ward G2 BSW) Axminster Aitken Bros. & Company
Axminster 3163 Stephens -James Ltd 35 High Bridge WARWICKSHIRE
70 Priory Road, Anfield Newcastle upon Tyne NE1 1EW
Liverpool L4 2RZ Newcastle upon Tyne 26729 Chas. H. Young Ltd
051-263 7829 170/172 Corporation Street
ESSEX Birmingham 4
F. E. Smith N.W. Electrics 021-236 1635
52 Great Ancoats Street NOTTINGHAMSHIRE
184 Moulsham Street
Chelmsford Manchester M4 5AB
061-236 6276 George Francis
Chelmsford 54594 93 Balderton Street
Newark YORKSHIRE
Croftfilm Ltd
Unique Radio Ltd 46 Friargate Newark 4733
6 The Facade, High Road Preston PRI 2AF Derwent Radio
Goodmayes, Ilford Preston 55244 28 Hillcrest Avenue
01-590 8277 Scarborough
Scarborough 63982
LEICESTERSHIRE Philip Cann Ltd
HAMPSHIRE SCOTLAND Chapel Walk, Fargate
A. K. Davey Ltd Sheffield SI 1GJ
Southern Marine Radio New Street, Hinkley
Hinkley 2173 and 4288 L. Hardie Sheffield 29225/6
(Southampton) Ltd 542 George Street
Solent House, Town Quay Aberdeen Short Wave (Hull)
Town Quay 22721 24a Newland Avenue
LONDON Aberdeen 20113 Hull, HU5 3AF
Wireless Supplies Unlimited Hull 408953
Imhofs (Retail) Ltd Larg & Sons (Dundee) Ltd
264-266 Old Christchurch Road 112-116 New Oxford Street 16-24 Whitehall Street R. A. Coates
Bournemouth W.C.1 Dundee 5 Bridge Street, Whitby
Bournemouth 24567 01-636 7878 Dundee 26061/2/3 Whitby 2622
Point to note by Advertisers in "Short Wave Magazine"-as well as covering
the U.K. radio amateur interest, we supply bookstalls all over the country,
also schools, libraries and the radio -electronics Industry258 THE SHORT WAVE MAGAZINE July, 1970
ARE YOU IN THE SPACE RACE ?
Get into Orbit with the NEW 47VIS ' ref
By Mosley of England
This new Vertical Antennae covers 4 Bands, 10, 15, 20 and 40 metres. Designed and manu-
factured 100% by Mosley of England. Can be used at ground level or mounted above ground,
comes complete with radial wire and the new ME -5 type insulators.
Power rated to I kW. A.M. and C.W. 2 kW. SSB. Height approximately 20ft.
Price ex works £18.0.0, carriage mainland 17/6
We can now supply the new ribbed Insulators (replacement for the old Eggs). Designed and
manufactured by us for Antennae uses. These are type No. ME -5. Price V- each.
Also the new Centre Dipole Types complete with cable clip, solder lugs and stainless steel
fittings to Antennae. Type ME-I0. Price 5/- each.
Rotators, Towers, Polythene cord and rope, Coax cable, Control cable, Twin feeder, SWR
indicators and many more Antenna accessories.
Send for HANDBOOK/CATALOGUE containing full details and prices of Antennae and technical
information, 35 pages, 2/6 refundable on purchase of an Antenna.
Atlas Carriage and Insurance Extra
Telephone: Coscessey 2861, orders only
Aidey
ra egetnuttcetd. 40, Valley Road, New. Costessey, Norwich, Norfolk Nor. 26K
EMSAC
CNI 2 metre converter. Nuvistor cascode design. Band- GVI All band vertical I-8-28MHz.
width better than 4dB over band. Measured NF less Immediate delivery Price 64.12.0 P. & P. 7/6
than 3dB. Complete with 38.666MHz crystal for GDI Multi band dipole 5RV type. 102ft. horizontal (I8g
28-30MHz. Polyanite). 110ft. feeder. Fibre glass encapsulations,.
Immediate delivery Price 69.10.0 P. & P. 4/9 Immediate delivery Price 64 P. & P. 4/6
CN2 CNI with power supply in attractive case. Mains
GD2 Smaller version of GDI. 55ft. top and 90ft. feeder.
lead, pilot lamp, on/off switch, etc. Immediate delivery Price 63 P. & P. 4/6
Immediate delivery Price 613.17.0 P. & P. 6/6
CN3 4 metre converter similar to CNI.
42MHz crystal for 28-30MHz output.
Complete with CRYSTALS from EMSAC
Price 0.10.0 P. & P. 4/6 HCI8/U 38-666MHz overtone type. Large stocks held. Return
post delivery guaranteed 25 /-
CN4 4 metre version of CN2. Price 613.17.0 P. & P. 6/6
HC6/U 40, 44, 45MHz overtone. Small stocks held; otherwise
PSI Mains Power supply suitable for CNI and CN3, 2-3 weeks 30/-
150v. at 15mA and 6.3v. at IA. Listed freqs. fundamental 4-8MHz ± kHz I I /-
Price 63 P. & P. 4/6 FT243
Your specified freq. fundamental 2-9MHz+ IkHz 21 /-
PRI 2 metre IG/FET Preamplifier. Gains in excess of Your specified freq. fundamental 2-9MHz, 0.005% 28 /-
15dB at low noise figure. Good cross modulation
characteristic. In aluminium box. Power required HC6 /U Listed freqs. fundamental I.2-19MHz± kHz 21 /-
116v. (approx) at SmA. Socket and plug provided. Your specified freq. fundamental 1.7-15MHz, 0.005%
Immediate delivery Price 64.15.0 P. & P. 4/6 40/ -
Listed overtone types I I-3-100MHz ± kHz 25/ -
KM, RF actuated keying monitor 50 and 75 ohms. May also Your freq. overtone types I 5-55MHz, 0005% 43/ -
be used as code practice oscillator. Provision for head- Your freq. overtone types 55-85MHz, 0.005% 50 /-
phones. Audio mixing facility. Pitch control. Volume
Control with on/of switch. Requires 9v. battery HC18/U Listed freqs. fundamental 4.3-20MHz, 0.005% 25/ -
(2-3ma) PP6. Smart case complete with loudspeaker. Listed overtones 20-126MHz, 0.005% 25/-
Price a P. Si P. 4/6 FT24I Your specified freqs. 370-540kHz± !kHz (These will
TU2 Antenna tuning unit for the Rx. 1.5-30MHz with pi - fit FT243 base) 25/ -
network, system switch, etc. Completely encased. All the above on 2-3 weeks delivery. HC6/U and
Price 64.10.0 P. & P. 4/6 FT243 bases 1/6 each. Crystals and bases post free.
The EMSAC range also available from G3RYV, 20 Allenby Road, Maidenhead, Berks. Tel : Maidenhead 22511. Evenings/weekends.
SAE with enquiries please
G3IAR ELECTRONIC & MECHANICAL SUB -ASSEMBLY CO. LTD.
HIGHFIELD HOUSE, ST. CLERE HILL ROAD, WEST KINGSDOWN, KENT Tel : West Kingsdown 2344Volume XXVIII THE SHORT WAVE MAGAZINE 259
iThe latest edition giving full
details of a comprehensive
LAFAYETTE HA.800 SOLID range of HI Fl EQUIPMENT,
STATE AMATEUR COMMU-
tales
COMPONENTS, TEST EQUIP-
NICATION RECEIVER SIX MENT and COMMUNICATIONS
EQUIPMENT. Over 230
BANDS 3.5-4, 7-7.3, 14-14.35, pages. fully illus-
21-45, 28-29.7, 50-54 Mc/s. trated and detail
mg thousands of
items -many at
bargain prices
FREE DISCOUNT
Dual conversion on all bands. 2 x 455 Kcis. mechanical filters. Product COUPONS
detector. Variable B.F.O. 100 Kc/s. crystal calibrator. " S " meter. VALUE 10f.
Huge slide rule dial. Operation 230v. AC or I2v. DC. Size 15" x 95" x 84-".
Complete with instruction manual, E57 /10 /-. Carr. paid (100 Kc/s.
Crystal 39/6 extra). SEND NOW -ONLY 716 P&P116
TRIO TS 510 AMATEUR UNR-30. 4 BAND JUST ARRIVED!!
TRANSCEIVER with speaker UR-IA SOLID STATE
and mains P.S.U., 6180. COMMUNICATION COMMUNICATION
TRIO JR3I0 AMATEUR BAND RECEIVER RECEIVER
10-80 Metre Receiver, E77/10/-. Covering 550 Kc/s.-30 Mc/s. Incor-
R209 Mk. II COMMUNICA- porates variable BFO for CW/SSB
reception. Built-in speaker and
TION RECEIVER phone jack. Metal cabinet. Opera-
II valve tion 220/240v. A.C., supplied brand
high grade new, guaranteed with instructions.
communi- 613 /13 /-. Carr. 7/6.
cation re-
ceiver suit- TRIO 9R-59DE
able for 4 band covering 550 Kc/s. to 30 Mc/s.
tropical continuous and electrical bandspread on
4 bands covering 550 Kc/s.-30 Mc/s.
use. 1-20 10, 15, 20. 40, and 80 metres. 8 valve
Mc/s. on 4 plus 7 diode circuit. 4/8 ohm output continuous. Special features are use
AM/CW/FM operation.
bands.
Incor-
and phone jack. SSB-CW . ANL .
Variable BFO . S meter
I II of FET transistors, S Meter, built-in
speaker and telescopic aerial,
Sep.
porates precision vernier drive,
.
bandspread dial . IF frequency 455 variable BFO for SSB reception,
B.F.O. Aerial trimmer, internal Kc/s. . audio output I5w. . Variable '111111111,11"111 1"'11111.1 1111' noise limiter, bandspread control,
speaker and I2v. D.C. internal RF and AF gain controls 115/250v. [11[1',1 sensitivity control. Output for low
power supply. Supplied in excellent A.C. Size 7" x 15' x 10" with impedance headphones. Operation
condition, fully tested and checked, instruction manual, E42. Carr. paid. 220-240v. A.C. or I2v. D.C. Size
E15. Carr. 20/-. 126" x 450 x 7". Excellent value.
TRIO COMMUNICATION TYPE HEADPHONES Norma ly Only 624. Carr. 7/6.
L5/19/6, our price L3 /15 /- if purchased with receiver.
HAMGEAR PRESELECTORS NEW CLASS D WAVEMETERS
Mains operated I.5-30 Mc/s.,
LAFAYETTE SOLID STATE HA600 RECEIVER
5 AM/CW/SSB amateur
Band A crystal controlled
El /10 /-. P. and P. 4/-. and short wave 50 Kc/s.-400 Kc/s. hetrodynefrequency
and 550 Kc/s.-30 Me/s. meter covering 1.7-
AR88 MAINS TRANSFORMERS F.E.T. front end. 2 Mechanical filters. Mc/s. Operation
Brand new, boxed, 59/6. P.P. S/-. Huge Dial. Product detector. on 6 volts D.C. Ideal
Variable BFO. Noise limiter, S Meter., for amateur use.
ADMIRALTY B.40 RECEIVERS 241." Band -spread. 230v. A.C./I2v.
D.C. Neg. earth operation. RF gain used condition
control. Size : 15' x 9r x 8l. a /19 /6. Carr. 7/6.
Wt. 18 lbs. Exceptional value, E45. or brand new with accessories
High quality 10 Carr. 10/-. 67 I 19 / 6 . Carr. 7/6.
valve receiver
manufactured TRIO JR.500SE AMATEUR RECEIVER CLASS D WAVEMETERS No. 2
by Murphy. Five 7 separate ranges between 3.5 and 29.7
bands 650 Kc/s.- Mcls. 7 valves, 2 transistors and 5 Crystal controlled 1.2-19 Mc/s.
30 Mc/s. I/F Mains or 12v. D.C. operation.
500 Kc/s. In- diodes plus 8 crystals : output 8 and Complete with calibration charts.
corporates 2
500 ohm and 5000 ohm phone jack. Excellent condition, 612/101-- Carr.
R.F. and 3 I.F. Crystal controlled oscillator. . 30/-.
stages, band-
Variable BFO VFO . AVC . ANL .
pass filter, noise limiter, crystal S meter . SSB-CW . Stand-by
controlled B.F.O. calibrator, I.F. switch special double gear dial
.
output, etc. Built-in speaker, out- drive socket for connection to a
put for phones. Operation 150/230 transmitter. 115/250v. A.G. Maim. TEI5
volt A.C. Size 191in. x 13fin. x 16in. Size 7 x 13 x 10in. with instruction TRANSISTORISED
Weight 114 lbs. Offered in good manual and service data, £65, Carriage paid. Package deal: JR500SE with GRID DIP METERS
working condition, 622/101-, Carr. SP5D speaker and HS4 headphones, 669 /10 /-.
Six ranges. .440 Kc/s.-
30/-. With circuit diagram. Also 280 Mc/s. Operates on
available B41 L.F. version of above. RCA COMMUNICATIONS 9v. battery. Full
15 Kc/s.-700 Kc/s., 117 /I 0 /-. RECEIVERS AR88D instructions. El2 /10
Carr. 30/-. Latest release by ministry BRAND NEW P.P. 3/6.
in original cases. 110-250v. A.C.
DUMMY LOAD RESISTORS operation. Frequency in 6 Bands.
Carbon 300 35w., 5/6. P.P. 1/6. II
535 Kc/s.-32 Mc/s. continuous output
impedance 2-5-600 ohms. Incorporating HANSEN SWR-3 BRIDGE
CRYSTAL CALIBRATOR No. 10 crystal filter, noise limiter, variable Impedance 52 ohms. Also operates
BFO, variable selectivity, etc. Price : as field strength indicator, com-
Small port- L65. Carr. E2.
able crystal plete with telescopic aerial, 69/6
controlled CLEAR PLASTIC PANEL METERS
each.
7/6 each.
P.P. 3/6. PL259 plugs to suit
wavemeter.
Size 7 x 7+ x First grade quality, Moving Coil panel meters, CODAR EQUIPMENT
4in. Fre- available ex -stock. S.A.E. for illustrated leaflet.
quency range Discounts for quantity. Available as follows. s. d.
500 Kc/s.-I 0 Type MR. 38P. 2I/32in. square fronts.
I
CR.70 Receiver ... 21 0 0
Mc/s. (up to I-0-1mA 27 /6 150mA 27/6 750v DC 27/6 CR.45 Receiver... ... 13 10 6
30 Mc/s. on 2mA 27/6 200mA 27/6 I5v AC 27/6
CR.45 Kit from... ... 10 10 0
harmonics). 5mA 27/6 300mA 27/6 50v AC 27/6 PR.30 Preselector 5 19 6
Calibrated 27 /6 500mA 27 /6 150v AC 27 /6
10mA PR.30X (Built in P.S.U.) 7 19 6
dial. Power 750mA 27/6 3v DC 27/6 300e AC 27/6 RQ.I0 Q Multiplier ... 7 5 0
requirements lamp 27/6 10v DC 27/6 500v AC 27/6 RQ.IOX (Built in P.S.U.) 8 17 6
300v. DC. 15rnA and I2v. DC 0.3A. 40 200µA 35 27/6 20v DC 27/6 S meter ImA CC.40 Control Unit .. 6 15 0
Excellent condition, 89 /6. Carr 7/6. 50-0-50uA37 /6 500µA 40 /- 5 amp 27 /6 100v DC 27 /6 32 /-
AT.5 Transmitter ... 16 19
100p,A 37/6 500-0-500uA 20mA 27/6 150v DC 27/6 VU meter42/- T.28 Receiver ... 15 19 6
100-0-100/4A 27 /6 50mA 27/6 300v DC 27/6 12/MS Mobile P.S.U. II 10 0
JOYSTICK AERIALS 35 /- ImA 27/6 100mA 27/6 500v DC 27/6 I2/RC Control Unit ... 2 10 0
Full range of Aerials and Tuners AT5 Mains P.S.U. 8 10 0
in stock. FULL RANGE OF OTHER SIZES IN STOCK. SEND S.A.E. FOR LEAFLET. Mini Clipper Kit 2 15 0
& Co. 3, LISLE STREET, LONDON, W.C.2
G. W. SMITH
01-437 8204
34, LISLE STREET, LONDON, W.C.2 01-437 9155
(Radio) Ltd. 311, EDGWARE ROAD, LONDON, W.I 01-262 0387
All Mail Orders to 147 Church Street, London, W.2 Tel.: 01-262 6562 Open 9-6 Mon. -Sat. (half day Thurs. at Edgware Road)260 THE SHORT WAVE MAGAZINE July, 1970
AMATEUR ELECTRONICS G3FIK
TRIO COMMUNICATIONS EQUIPMENT. We are now in a position to offer full demonstration facilities on all items in the TRIO range for the
caller and as previously stated it is our policy to provide the prospective purchaser with a completely unhurried opportunity to actually try each piece
of TRIO equipment ' on the air' without any obligation whatsoever to purchase. Whilst on the subject of TRIO equipment it would seem a good
opportunity to mention the TS -510 TRANSCEIVER which although now widely used is still perhaps not fully appreciated by the uninitiated. Our object in
raising this is prompted by the remarks that are sometimes passed at Rallies and Club meetings to the effect that the TS -510 is presumably a Mark II
version of the TS -500. This of course could not be further from the truth as the TS -510 has very little in common indeed with its predecessor and repre-
sents a truly complete re -design, with the resultant incorporation of many features which the TS -500 did not have. To the man who is contemplating
the purchase of a transceiver there is, without doubt, no better buy on the U.K. market at the time of going to press and it would be well worth a glance
at the excellent brochure on the TS -510, which we would be pleased to forward by return of post. Remember, this equipment carries a 12 months'
guarantee backed by a first-class after sales service.
Below is our current list of used equipment which is priced to include carriage, except where stated.
RACAL RAI53A. TWIN CHANNEL RECEIVER, This E s. d. HEATHKIT RA-I RECEIVER. Complete with homebrew E s. d.
is an extremely rare receiver based upon the famous RAI7 Q Multiplier unit ... 25 0 0
but incorporating two channels for diversity reception. The HEATHKIT RG-I RECEIVER. Mint condition ... 35 0 0
same features of read-out, stability, sensitivity and selecti-
vity are employed and the same frequency coverage as the MINIMITTER HAMBAND CONVERTER (1.6 Mc/s. IF)
RAI7 is provided. Four IF's are used, 40 Mc/s, 2-3 Mc/s., Used condition ... O 0
1.6 Mots. and 100 'Volume XXVIII THE SHORT WAVE MAGAZINE 261
TRIO'S TS -5110
Urikk-ACCURAVIE RECEIVER
TRIO's TS -510 has opened countless SSB vistas TS -510 SSB TRANSCEIVER
Receive and Transmit Frequencies:
through its creative design that enables it to 3.5 MHz -29.7 MHz
operate at constant maximum power with top Receive Sensitivity:
durability. This transceiver uses a high frequen- 0.5PV, S/N-ratio of 10 dB-at 2.5 MHz -21 MHz
cy crystal filter and covers all ham bands from 1.5P -V, S/N ratio of 10dB at 28 MHz
3.5-29.7 MHz. Because the TS -510's frequency DIMENSION -S: 13"(W), 7"(H), 13-5/8"(D).
VFO-5D VARIABLE FREQUENCY OSCILLATOR
coverage has been compressed to 25 KHz for Frequency Range: 3.5MHz-29.7MHz
one complete dial rotation, tuning in on SSB Oscillator Method: VFO unit-clapp Osc. Circuit
signals is easy. By using TRIO's PS -510 (Power Xtal Osc. Unit -Pierce C -B Circuit
supply and speaker) and VFO-5D (Variable fre- DIMENSIONS:
7-7/8"(W), 8-21/32"(H), 7-9/16"(D)
quency oscillator) optimum results may be ob- PS -510 POWER SUPPLY AND SPEAKER
tained. The PS -510 operates on an AC power Designed as an A. C. power supply unit exclu-
supply through a 6-1/2" speaker. The VFO-5D sively for the SSB transceiver TS -510
has a double -gear dial covering 25 KHz per 6-1/2"communication speaker is incorporated
DIMENSIONS: 8"(W), 7-1/8"(H), 14-5/8"(D)
rotation.
TRIO
the sound approach to quality-
TRIO ELECTRONICS,
TRIO KENWOOD ELECTRONICS S.A.
Sole Agent for the U.K.
160 Ave., Brugmann, 1060 Bruxelles, Belgium
B.H. MORRIS & CO., (RADIO) LTD.
84/88, Nelson Street, Tower Hamlets, London E.1, Phone: 01-790 4824262 THE SHORT WAVE MAGAZINE July, 1970
LOWE ELECTRONICS N. W. ELECTR1CS
WELLINGTON STREET, MATLOCK,
DERBYSHIRE 52 GT. ANCOATS STREET
Matlock 2817 (2430 after 6 p.m.) BILL G3UBO MANCHESTER 4
AGENTS 061-236 6276
(evenings and weekends only)
Alan : G3MME
4 Southwick Street, Southwick, Brighton
Southwick 4887 G3MAX
Sim : GM3SAN EDDYSTONE AND TRIO RECEIVERS.
19 Ellismuir Road, Baillieston, Nr. Glasgow DIECAST BOXES. JACKSON CAPACITORS
041-771-0364
AND DRIVES. DENCO COILS. " RADIO -
About time I mentioned second-hand stuff for a change, so cast an SPARES" TRANSFORMERS AND COM-
optic over, or take a perfunctory butcher's at the stuff listed below.
PONENTS.
Before 1 forget-although we'll be at the R.S.G.B. Exhibish 19th -
22nd August, we'll be CLOSED THE REST OF THE MONTH.
I will be huddled under an umbrella in the teeth of a howling gale
on some rain -sodden beach. " Cor," the locals will say, and they 898 GEARED DRIVE ASSEMBLY. Still available at old price
ALWAYS say it, " worst August we've ever had-you should have E6 6s. 8d., post 4/6.
been here last month." Ah well, bash on. So when you 'phone up
at 11.30 p.m. wanting something right away, it's a case of Harry
Toughers Ole Boy, 'cos I'll be away and we're CLOSED AUGUST AR88D. Communications receiver. Brand new, with spares,
except for aforesaid EXHIBISH. Heigh nonny no, get flogging, handbook, etc., E85, carriage LI.
Lowe.
NEW SEQUENCE RELAY. 375 ohm coil. 4" x 2k" x 1", I pole C/O.
2 make, I break, 15/-, post 2/6.
Sommerkamp and Inoue, of course, and the new FE -600, which for
a 200W p.e.p. 5 band transceiver ain't bad value at £165, complete
ready to go. Chances are I'll be sold out, though. Lots of other SEALED RELAY. 2 pole C/O. 170 ohm or 700 ohm coil. If" x
goodies that I usually advertise, however, and in the second-hand If" x 1", 5/-, post 1/-.
line:-
Receivers SANGAMO WESTON RELAY. 10F/18051.S115. -2/0/-2 mA'
movement. Twin coil. 110 ohm. 47 ohm. single pole C/O -centre
Trio JR-500, E45 FR -100B, £85 off. With plug in base. 2" x I" x i", 25/-, post 2/6.
Lafayette HA -350, E55 RG I, E25
Hallicrafters SX-I 1 I and match-
ing speaker, E60 SP -600,£85 GPO COUNTER. 4 digit. Indicator face If" x x 5" long.
Eddystone EA -I2, E110 H.R.O. p.s.u., 5 coils, MB 2,300 ohm coil, 4/6, post 2/-.
KW-77-late model with blue H.R.O. p.s.u. B.S. coils, E20
front panel, £70 Lafayette HA -600, £40
BC -639A-100-155 MHz. Re-
Eddystone 840C, E30
HIGH SPEED RELAY. Twin 50 ohm coil. Single pole C/O
quires p.s.u., but very clean 2f" x 1" x .1", 7/6, post 2/-.
and respectable -looking, £12 Eddystone 888A, £60
Hallicrafters SP44 panadaptor AR88 cabinets by Philpotts,
(455 kHz), £25 new, £5 RELAY. S.P. change -over. 2 pair make. 1,100 ohm coil. 3" x
If" x 1", 6/6, post 2/-.
Transmitters
FL -200B, £95 DX4OU and VFIU, £20 SEALED RELAY. 4 pole C/O. 150 ohm coil. 2" high, I" dia.,
FL -I000 linear, £70 10/-, post 2/-.
Hammarlund HXL. One linear, SBIOU, f20
£100 DX100 and SBIOU,
CONTINUOUS ACTION SWITCHING UNIT. Type 273.
Transceivers Single pole C/O. Can be used for flasher. Platinum contacts for
long term use. Coil Res. 285 ohm, 12 volt, 4" x 2" x 2", 10/-,
Drake TR3, £200 Paros, E100 post 2/6.
KW -2000B, £220 (never used) KW -2000 and A.C. and D.C.
p.s.u's, EI40
KW -2000A, £170, (choice of 3) Swan 350, E170 TWIN COIL RELAY, 666 ohm. coil -I pole C/O.
I pair I
KW -2000 and A.G. p.s.u., E120 Hallicrafters Tornado, £135 make. coil -I pole C/O pairs break. Can be operated singly or
I
paired, 12/6, post 2/-.
In addition, we usually have the odd bit of test gear and station
sundries-send me a large s.a.e. and I'll tell you all about it, includ-
ing the new FE -600. Got gear to flog ? Test gear ? If it's nice, we'll SMALL POWER TRANSFORMERS. Drop through Mtg.
either buy it or flog it for you on commission. 3" x 2k" x 2+". Above chassis, postage is 4/6 each. 240v. 100mA.
6.3v. 2A IT. 25/-. I80v. 40mA. 6-3v. 2A LT, 17/6. 180v. 25mA.
Want H.P.? No problem. 6.3v. 2A LT, 14/-.
Finally, may I remind you-see you at the R.S.G.B. Exhibish 19th -
22nd August, but we're CLOSED the rest of AUGUST. Yeah, I
know-three times I've repeated myself, but even so I'll bet you CONTACT COOLED RECTIFIERS. Postage 1/- each. 250v.
ten to one that several hundred chaps, " Always read your ads, 75 mA, 9/6. 250v. I25mA., 12/6.
Bill, first thing I turn to." will be playing merry hell with me when
they get no reply to their 'phone calls
Some items left from previous adverts.
73 de Bill
P.S. Don't forget our Motorway service for new and second-hand Business hours : 9 a.m.-6 p.m. Tuesday -Saturday
gear, even if you only want to look at it.
CLOSED ALL DAY MONDAYVolume XXVIII THE SHORT WAVE MAGAZINE 263
THE SENTINEL LOW NOISE FET PRE AMPLIFIER
If you are in doubt about the performance of your two metre converter this
pre amp will give you less than I dB noise factor and 20dB gain with low HAMG EAR ELECTRONICS
performance converters.
In neat aluminium box, size 2.1" x 3-} x I£'. Price L6 10s. Od. Try this preselector
THE SENTINEL DUAL GATE MOSFET 2 METRE CONVERTER on your communica-
tion receiver, a pen-
Dual gate MOSFET cascode circuits for the RF amplifier and mixer for excellent tode amplifier with
overload and cross modulation performance. Noise figure 2dB. Injection built-in antenna
stages -silicon planar VHF transistors and a VHF crystal. Supply 12-18 volts coupler covering from
IF's 4-6MHz, 9-1 IMHz, 14-16MHz, 23-25MHz, 28-30MHz. 1.8 to 32 mc/s com-
Available either: - pletely. A gain of up
in a neat aluminium, stoved silver hammer enamel box size: 2+" x 3.1" x li". to 25 Dbs, improving
Price £12 10s. Od. image rejection and
low level signals. A
or printed circuit module alone -fully aligned with flying lead connections new low line case blue
Size 2+" x 21". Price E1.1 Ss. Ocj silver with ultra
N.B.-All components are new, branded components and whenever practical modern controls.
our policy is to specify British components. Mains powered. Price
E7. 16. 0. send for
All items should be ex stock but a phone call will give immediate confirma- details.
tion.
SOLID STATE MODULES 29 CARLYLE ROAD, NORWICH
14 DALTON GREEN LANE, HUDDERSFIELD HDS 9YE
Telephone : Huddersfield 25173
63982 DERWENTRAVINE,
RADIO =1/46
SCARBOROUGH G3LRB G3MCN
SHOWROOM, 5 COLUMBUS
KW Atlanta and AC p.s.u. £250 Garex heavy duty p.s.u. kit L4 12
KW 2000B and AC p.s.u....
KW Vespa II and AC p.s.u.
£240
£135
Garex dual p.s.u. kit
Eddystone 0/7 ...
... L6 18
£285 STEPHENS-JAMES LTD.
KW 201 receiver ... Elll Eddystone Edometer £27
Trio JR3I0 ... ... L77.10
KW GI multiplier ... £8 10 Eddystone 940 ... E158 KW Atlanta. Transceiver L250
KW E -Z match ... ...1I3 10 Eddystone EA 12 ... £195 KW200B. Transceiver ... L240 Trio 9R59DE. Receiver 142.10
KW P.E.P. meter ... ...LI6 10 Eddystone EC 10 ... -159 10 KW Vespa. Transmitter E135 Trio Headphones ... £5.19.6
KW 3 way coax AE switch £3 3 Eddystone EC 10 Mk. II...E69 10 KW201. Receiver ... LI I I Trio SPSD Speakers ... £4.7.6
KW balun ... LI 15 Eddystone mains p.s.u. ... £6 15 KWI000. Linear ... E125 Lafayette HA600 ... L45
KW traps and T piece ... L3 10 Eddystone 898 dial E6 6 KW E -Z Match ... L13.10 Lafayette HA800 ... £57.10
KW low pass filter ... £4 14 Eddystone plinth speaker L4 6 KW Balun £1.15 Eddystone EAI2 ... £195
KW trap dipole ... ...LI I 10 Valves 6146 ... ... 30/ - KW Antenna switch ... E3.3 ...
52/- KW Low Pass Filters . £.9 Eddystone 940 £158
KW dummy load ... E5 10 RCA 61468 Eddystone ECIO Mk. II £69.10
Lafayette HA600 £45 Diecast boxes 8/3, II /II, 18/11 Trio TSSIO. Transceiver E180
Lafayette HA800 £57 Codar AT -5 transmitter -E16 19 Trio J R500. Receiver ... £69.10 Eddystone EB35 ... £132
Unica URIA £24 Coder T-28 receiver ...EI5 17
Channelmaster E19 Codar 2.50/S al 10
Ball bearing guy ring ... 37/ - Codar 12/MS ...LII 10 Superior performance mobiling with the G -WHIP range of antennae.
Trio JR 310 ... E77 Coder 12/RC ... £2 10 Lightweight design. Helical wound. " Ranger I60m." /7.10. 160/80m.
Trio TS 510 and AC p.s.u. £180 Coder PR -30 ... £5 19 duo -bander, E9. Tribander 10-15-20m., £9.9. Basemounts, E1.9.6.
Trio JR-500 receiver ... L69 Coder PR -30x ... ... a 19 Full details sent on request. New Multimobile self-selecting 5 band
Trio 9R59DE receiver ... E42 Joystick SM £5 10 without coil changing. Luxury mobiling.
Trio SP -5D speaker ... E4 7 Joystick standard ... E5 10
Trio HS -4 headphones ... £5 19 Joystick de -luxe ... E6 II
Eagle SWR bridge ... £9 19 Joystick 4RF tuner E7 2
Eagle RF 45 tuning meter 12 Joystick 6RF tuner E4 10 Hy -Gain Antenna Range Second-hand Equipment
Medco LP filter, Belling... £4 10 Joystick 3A tuner... ... L4 4
Medea LP filter, Amphenol LS Acos mic 45 Verticals : ... ... EI70
6/- KW 2000A
Medco HP filter ... ... 27/6 Amphenol PL 259 ptfe ... I2AVQ 10-15-20m.... LI3.10
250 ohm carbon pots ... 5/ - Amphenol SO 243 ptfe ... 7/6 14AVQ I0 -15-20-40m. E19.10 RQIO Q Multiplier ... £7
Jackson 4103 dial ... 24/ - Repanco coils and trans- 18AVQ 10 through £32.10 KW77 with speaker ... E65
Jackson C804 25pf var ... 4/6 formers. 80m. ... ...
Hallicrafters SX 122A E199 100 kcis. B7G xtals Hansen SWR ... E3
Hallicrafters SX 133 ... £149 Selection 50 -odd xtals, our Beams :
Trio 9R59DE ... £37
G Whips 160/80 ... E9 choice ... L2 TH3MKC Tribander... E67.10
G Whip tribander 14-28... E9 6JS6A valves, RCA 35/-
... * TH2MK Tribander ... £44.10 Eddystone 840C 148
G Whip multi mobile ...£15 10 6L66 valves, RCA... ... 46/- TH3Jnr. Tribander .- £44.10 AR88D ... ... ... E40
G Whip base mount ... LI 10 6GIC6, RCA ... 16/- Hansen 50 ohm SWR
Garex 2m. converter Halson mobile Ae E6 17 Bridges ... ... E4
KW500 Linear ... £55
28-30 Mc.... ... ...L10 7 Halson extra coils ... E3 17 Hansen FS Meters ... E2.15 BRT400 Rx ... ... £65
Garex 2m. tx £13 IS TTC 5 band RF meter ... E3 19 TTC RF Meters, tunable £3.19.6 ECIO 24v. supply £4
Garex 20w. 2m. tx ...LIS 10 Antex soldering iron 15w. LI 12 High Pass Filters
Garex lOw. 2m. tx kit ... E4 17 Antex soldering kit ... L2 7 Semi -automatic Bug Keys E4.10 10 metre G -Whip ... £2.15
Garex Standard mod. kit £4 15 2 way intercom ... E2 15 PL259 Plugs ... ... 6.0 KW E -Z Match ... LIO
Garex de -luxe mod. kit ... E7 17 Shure 201 mic. £5 10 PL259 Cable Reducers ... 2.0 Trio JR500 ... £50
Garex popular p.s.u. kit ... E3 15 Wellar solder gun ... 78/ - PL259 Sockets -. ... 6.0
Garex xtal checker ... 70 /- Hansen swr bridge ... E4 TECH 15 G.D.O. ... E12.10 Eddystone 940 ... E100
PTT dynamic mic. ... 39/6
Wanted: We are always pleased to hear about your trade-in equipment
and are looking for good condition KW, Eddystone, and TW items in Codar Equipment 2m. 5 element Beams ... £2.9.6
particular. We can offer cash, radio equipment or new photographic ATS. 160/80 Transmitter E17 2m. 8 element Beams ... E3.2.6
equipment in part exchange. AT5 A.G. p.s.u.... ... Efl. 10 Garex. 2m. Mobile Tx ... E42.10
PACKAGE DEALS. WE CAN BEAT ANY ADVERTISED OFFERS. GIVE D.C. Mobile p.s.u. ... LI I .10
US A RING Antenna Rotators :
H.P. on any items over C35 in value. One third deposit and up to two years PR3OX Preselector ... £8.10 E15.9.6, £18.18.0, E25, E40
T28. I60/80m. Receiver £16.10
to pay. Payments may be by Post Office Giro. You may also place your orders RQ10 " Q " Multiplier... £8.17 All RSGB Publications Stocked.
by Giro. Our account number 64 041 0006.
Second-hand equipment in stock
£200 Codar AT -5 £13 Complete range of Eddystone and Datum diecast bases now in stock.
DX40 £20 Codar T-28 112 " Stella " cabinets, chassis, panels. Full details for S.A.E.
HW30 £23 Lafayette HA 500 £38
KW77 Inoue IC 700R £75
CR100 . 212 Eddystone EA 12 ... £140 300 ohm twin feeder, yd. 8d. Jackson SM dial
Star SR 550 E35 KW Viceroy II and p.s.u.... £80 75 ohm twin feeder, yd. 8d. Eddystone speaker ... E3.7.6
Beam 10m yagi E14 Heath RA -1... L30 Dipole " T " pieces .. 2.6 Low Pass Filters ... £5.9
£33 Hallicrafters SX Ill ... £70 50 ohm co -axial cable, yd. 2.0 Leson PTT. Mits. ... a .19.6
Eddystone 840A E30 Pye Lowband reporter ... £5 Eddystone 898 SM dial ... E7.5.0 24 -hour Digital Clocks
KW 2000A and AC p.s.u... 1190 Hiband ranger ... EIO £14 and E21
KW Vespa and AC p.s.u.... E1 15 Heath RG-1... L27
KW Valiant and DC p.s.u. L30 Trio 9R59De £33
H.P. and Credit items arranged on all orders over £35. Part exchanges
Trio JR 500 . £55 Hallicrafters 585 ... L30
Trio TS and AC p.s.u. £150 AVO 8. Mint ... £17 welcome. Carriagelpostage extra al/ items. S.A.E. enquiries please.
Hallicrafters SX 43 ... £35 KW Vanguard 160-10 ... £48
Trio VFO - £20 Hallicrafters SXII0 ... £60
Minimitter Mercury tx ... £30 Drake SW4A E155
Collins filter
Please add extra for carriage. S.A.E. for lists
70 Priory Road, Anfield, Liverpool 4
Our holiday period this year is July 23 to August 7. We shall be Tel. 051-263 7829. Half -day Wednesday.
attending the rallies at South Shields, Scarborough, Derby and No parking problems.
Scotland if they don't hold it at John o' Groats, hi.
28 Hillcrest Avenue, Scarborough, Yorks. We are approximately i mile from the Liverpool and Everton Football grounds.264 THE SHORT WAVE MAGAZINE July, 1970
Technical Books and Manuals
AERIAL INFORMATION Shop & Shack Shortcuts . 34/6
Television Explained Vol. I . . 26 /6
ABC of Antennas. . 17/- Television Explained Vol. II 26/6
Aerial Handbook . . . . 15 /9 World Radio & TV Handbook 1970 .
Amateur Radio Antennas (Hooton) 0/P Edition . 43/6
Antenna Handbook, Volume 1 . 33/6
Antenna Round -Up, Volume 1 . 27/6
Antenna Round -Up, Volume 2 . 3316 HANDBOOKS AND MANUALS
Antenna Handbook, 11th Edition . 26/6 Amateur Radio DX Handbook 42 /-
Beam Antenna Handbook 40/6 Electronic Circuit Handbook, Vol. 1 27/6
Ham Antenna Construction Projects 27 /- Electronic Circuit Handbook, Vol. 2 27/6
Quad Antennae . 35 /- Mobile Handbook, CQ . . 27 /-
S9 Signals . 17 /- Mobile Manual, ARRL . . 27/-
New RTTY Handbook. . . 35 /-
New Sideband Handbook, CQ . 28 /-
BOOKS FOR THE BEGINNER Novice Handbook Tx & Rx . . 35 /-
1970 ARRL Handbook (paper) 55
Amateur Radio (Rayer) 26/6 1970 ARRL Handbook (cloth bound) . /-
Basic Mathematics for Radio and Radio Communication Handbook(RSGB) 69 /-
Electronics . . 0/P Radio Handbook, W.I. Orr (18th) . . 111/-
Beginners Guide to Radio 0/P Surplus Conversion Handbook . 26 /6
Beginners Guide to Electronics 16/- Transistor Substitution Handbook 19/ -
Beginners Guide to Colour TV 15/8
Better Short Wave Reception 35 /-
Course in Radio Fundamentals 11 /9 USEFUL REFERENCE BOOKS
Dictionary of Electronics . 8/6 Amateur Radio Techniques . . 14/3
Foundations of Wireless 23/- Amateur Radio Construction Projects 0/P
Guide to Amateur Radio (N.E.) 8/10 Amateur Radio Circuit Book . 13/4
How to Become a Radio Amateur . 11 /- Elements of Radio Engineering . 16/ -
Morse Code for the Radio Amateur 2/4 Guide to Amateur Radio (N.E.) 8/10
Learning the RT Code . . 4/9 Engineers' Pocket Book . 15/10
Novice Handbook, Tx & Rx . 35/- Hams' Interpreter . . . 10 /6
Radio, by D. Gibson . . . 13 /9 Hints & Kinks, Vol. 7 (AR. RL). . . 11/9
Radio Amateur Examination Manual 5/9 Radio Amateur Examination Manual . 5/9
Short Wave Listening .
16 /- Operating an Amateur Radio Stat. . 3/ -
Short Wave Listener's Guide 0/P Radio Amateur Operator's Handbook 6/6
Short Wave Receivers for the Beginners 0/P Radio Valve Data . . . . 11/8
Understanding Amateur Radio . 26/6 Radio Data Reference Book . . 14/6
Radio Engineer's Pocket Book . . 12/6
Service Valve & Semiconductors Equiva-
GENERAL lents . . 5 /6
(Amateur) SSB Radio Guide . . 31/ -
Official (I.T.U.) Chart of International Single Sideband for the Radio Amateur
Frequency Allocations . 37 /- (ARRL) . . .
26 /6
CQ Anthology 1952-59 27/6 Surplus Schematics (CQ) . 23 /6
Eliminating Engine Interference 17/- Q & A on Audio . . .
10/-
Guide to Broadcasting Stations 0/P Q & A on Electronics . 10/-
How to Listen to the World . 2616 Q & A on Transistors 0/P
Introduction to Valves . . 9/4
Radio Experiments (Rayer) 17/3
RCA Silicon Power Circuits. 231- VHF PUBLICATIONS
RCA Receiving Tubes Manual 30 /- VHF Handbook, Wm. I. Orr 35 /-
RCA Transistor Manual (N.E.) 30/- VHF Manual (ARRL) . . 26/6
RCA Transmitting Tubes . 15 /- VHF for the Radio Amateur 0/P
Radio Astronomy for Amateurs 0/P VHF /UHF Manual (RSGB) 23 /-
The above prices include postage
Available from SHORT WAVE MAGAZINE
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(Counter Service, 9.30-5.15, Mon. to Fri.) (Nearest Station: St. James's Park)
(GIRO A /C. No. 547 6151)Volume XXVIII THE SHORT WAVE MAGAZINE ,65
LOWE ELECTRONICS
WELLINGTON STREET, MATLOCK, DERBYSHIRE
Matlock 2817 (2430 after 6 p.m.) BILL G3UBO
AGENTS
(EVENINGS AND WEEK -ENDS ONLY)
Alan G3MME Sim GM3SAN
4 Southwick Street, Southwick, Brighton. 19 Ellismuir Road, Baillieston, Nr. Glasgow.
Southwick 4887 041-771 0364
FT500 FR500
a 0 et
0
500W PEP
Top band to 2m.
VOX, PTT, MOX. 100 and 25 kHz marker RIT, Metered ALC.
All the usual optional extras fitted as standard, £250. With extra The no compromise AM, FM, SSB and CW receiver for the man
6 xtal CW filter, E270 who wants the best, E160
FT250 FL500
ct (i) 0 0
240W PEP J
240W PEP
VOX, PTT, MOX. 100 kHz marker. RIT Metered ALC. Again,
usual extras are standard, E160, p.s,u., E45 Companion to the FR -500 for transceive or split frequency.
Matching it in quality and performance, E145
FTI50
FL2000
120W PEP
All -transistor except driver and PA. Both AC and DC power To complete the station, there is the FL -2000 linear. 1200W
supplies built-in. Specially designed for mobile. VOX, PTT, PEP input. Comfortable legal limit output. Built-in SWR meter,
MOX, 100 kHz marker, RIT, £215 etc., E110
Hear them - any band, any part of the world, any time
Try them - at Matlock, or any of the Agents266 THE SHORT WAVE MAGAZINE July, 1970
HOME RADIO (Components) Ltd., Dept. SW.
234 London Road, Mitcham CR4 3HD.
Heathkit for Telephone 01-648 8422
SW Receivers
the choice is yours ...
Prove for yourself how easy D.I.Y. kit
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Purchase a Home Radio Catalogue,
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13
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11.001114 Whether or not you want to use
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ADDRESS I I
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ADVERTISERS
PAGE
SHORT WAVE
Amateur Electronics (G3FIK)
Baginton Electronics ...
Belding & Bennett (Radar)
260
318
320
MAGAZINE (GB3SWM)
J. Birkett 314
Daystrom 266
Derwent Radio 263
Echelford Communications 316 Vol. XXVIII JULY, 1970 No. 321
Eddystone Agents 257
Eley Electronics 314 CONTENTS
EMSAC 258 Page
Editorial ... 269
G. R. Grigg 313
Clean CW Keying, by I. E. Hill, G6HL 270
G.W.M. Radio 319
Electronic Morse Code Generator, Part II, by G. E. Goodwin, G3MNQ 272
Hamgear Electronics 263
QSY Down with a Crystal, by G. P. Anderson, G2Q Y 276
Henry's Radio ... 313
Narrow -Band Frequency Modulation, by J. H. G. Allsop, G3OG X 276
Home Radio, Ltd.... ... 266
Modification for The HRO, by P. Talbot... ... 277
H. & W. Electron Devices 313
Mechanical Design for QRO VHF Transmitter,
Imhof . 317 by B. A. Pickers, G3 YUA 278
K.W. Electronics inside front cover The Mobile Scene ... 280
Lowe Electronics ... ... 262, 265 " SWL "-Listener Feature, by Justin Cooper 283
Minitenna 313 HPX Tables-New Rules 288
Mosley ... 258 Communication and DX News, by E. P. Essery, G3KFE 289
Graham Newbery . 260 VHF Bands, by A. H. Dormer, G3DAH 296
N.W. Electrics 262 Marconi Commemoration Station, GB3FI, by D. H. Adams, GW3VBP 303
Partridge Electronics back cover, Special -Activity Stations ... 305
313, 315 The Month with The Clubs-From Reports 306
Partridge (G3PRR) inside back cover The Other Man's Station-G3WRO 310
Peter Seymour ... ... 260, 314 New QTH's 311
Radio Shack inside back cover, 312
R.T. & I. Electronics, Ltd. 312
Senator Crystals inside back cover Managing Editor: AUSTIN FORSYTH, O.B.E. (G6FO/G3SWM)
Small Advertisements ... 315-320
Smith, G. W. (Radio) 259 Advertising: Maria Greenwood
Solid State Modules 263 Published at, 55 Victoria Street, London, S. W.1, on the last Friday of the
Spacemark, Ltd. ... 313 month, dated the month following. Telephone: ABBey 5341/2
(STD 01-222-5341)
SSB Products ... 319
Annual Subscription: Home: 45s. (48s. 1st class) post paid
Stephens -James, Ltd. 263 Overseas: 45s. ($6.00 U.S.), post free surface mail
S.W.M. Publications inside back
Editorial Address :
cover, back cover, 264, 268 Short Wave Magazine, BUCKINGHAM, England
Taurus Electrical Services 314
AUTHORS' MSS
Telecomms (G3SED) 317
The Amateur Radio Shop 314 Articles submitted for Editorial consideration must be typed double-spaced
with wide margins on one side only of quarto or foolscap sheets, with diagrams
Trio (Japan) 261
shown separately. Photographs should be clearly identified on the back.
J. & A. Tweedy (Electronic Payment is made for all material used, and it is a condition of acceptance that
(Supplies) Ltd.... 316
full copyright passes to the Short Wave Magazine, Ltd, on publication.
VHF Communications 313
Western Electronics 315 C Short IVave Magazine Ltd.
F.. & O. E. 267268 THE SHORT WAVE MAGAZINE July, 1970
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New Titles
BUILDING YOUR AMATEUR RADIO NOVICE STATION by W7OE ... (post free) 30/-
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101 QUESTIONS AND ANSWERS ABOUT TRANSISTORS by Leo G. Sands f 25/6
AMATEUR RADIO MOBILE HANDBOOK by W6NJV 25/6
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(GIRO A/C No. 547 6151)FOR THE RADIO AMATEUR AND AMATEUR RADIO
SHORT WAVE
EDITORIAL
Cards The subject of QSL'ing in the SWL context has been touched upon often
enough over the years - but there are always some things that need saying
again, and again.
The lure of DX makes heavy demands upon its devotees - and not least is that of obtaining
firm confirmation of what is entered in the log. To most operators (transmitting and SWL)
seriously interested in DX, the QSL card is an essential factor in the scheme of things, crown-
ing results with the proof of ability.
From the point of view of the transmitting operator putting in a good deal of time working
the DX bands, things have become very difficult. Cards are often just as important and
interesting to him as they are to the SWL, but with quite a different emphasis. He sends, and
hopes to receive, QSL's to confirm contacts. And with the volume of traffic on the amateur
bands today, this is about as far as he can cope. SWL reports are of little interest to him unless
he wants them for a coverage survey (which, incidentally, few transmitters appear to attempt
these days), or they tell him something that he could not otherwise know. For instance: That
he is being heard in an unexpected direction at an unusual time; or that his CQ was answered
by some exotic DX station, unheard; or, that in comparison with other stations in his neigh-
bourhood, he was stronger, or weaker; or that, though he called, and called, and called without
result he was being heard by an SWL able to give a detailed report.
The operator behind a call DX for his country of origin is not only burdened with the task of
QSL'ing the stations he has worked, but is also (if a regular phone station) flooded with
SWL report cards - many of which originate in the U.K. even where G operators are con-
cerned !
In such a case, there can these days be no obligation to QSL, even if an s.a.e., a stamp or an
IRC is enclosed. The point is that no AT -station operator can be expected to QSL all and
sundry merely for the asking, because time for him is just as important a factor as postage.
But the good amateur will always respond to an SWL report which is of real use to him, even
if no return postage has been offered. And a good SWL only sends a report where he thinks
it is wanted, or could be uselid.
WORLD-WIDE COMMUNICATION270 THE SHORT WAVE MAGAZINE July, 1970
CLEAN CW KEYING would go, the transmitter keyed on and off and he was
making lots of contacts so he saw no real need to do
more. Perhaps unfortunately, he had no goggle box
IMPORTANCE OF GOOD SHAPE gazers to get annoyed and demand action. Forty years
later we still seem to have a similar situation and attitude
FACTOR in many quarters.
Keyed Waveforms
I. E. HILL (G6HL)
It is convenient to start with the simple cathode -
keyed amplifier, consider the shape of the signal obtained
FVERY Amateur Radio handbook carries a chapter by keying and note its effect in a receiver. Using a
on transmitter keying and identifies methods of key neutralised tetrode, the conventional circuit will be as in
click elimination, yet a remarkable number of active Fig. 1, with key connected as shewn ; the resultant wave-
CW operators either do not fully understand the problem, form should be as in Fig. 2 but is more likely to look
are incapable of applying the cure, are regardless of the like Fig. 3. The abrupt change from no input to maximum
havoc they cause in congested bands, don't listen to will be resisted by circuit constants and a clean start is
their own signals, just can't read, or perhaps are guilty unlikely. Typically, one can often see on a 'scope a very
of the whole flaming lot! There are also the chaps who short break in transmission immediately following the
can't produce a stable DC CW signal and then even try start. If you don't believe it, feed RF to the Y -plates of
to modulate it, but that is another story. an oscilloscope via a pick up wire and tuned circuit-
Particularly to near neighbours (and in the HF Fig. 4. Run the oscilloscope time base slowly; if it is
bands they can be hundreds of miles away) badly keyed synchronised to the speed of an auto-keyer the wave-
blurp signals are a curse and add to frequency congestion. form can be held stationary for examination.
The annoying thing is that it is all so unnecessary and
so easily avoided. This story has been told before but The Receiver
no apology is offered if by repetition a few offenders The effect on the receiver is twofold. The unclean
can be persuaded to put their houses in order. start of the signal of Fig. 3 will give a scratchy noisy
Years ago, when living in Africa, the writer had a effect and the abrupt start and stop will generate
near neighbour who used a 250 -watt self-excited oscillator transients heard as loud clicks which persist on either
with a T250 valve which he keyed by making and break- side of the carrier frequency, sometimes spreading 100
ing the grid return to earth. A wide -gap relay was used of more kHz. Even the apparently clean signal of Fig. 2
because there was RF on the leads and the contacts will generate transients and loud clicks in the Rx. These
sparked freely, causing an appalling noise in local clicks do nothing to improve readability of the signal-
receivers. After lengthy discussion he eventually accepted in fact, they have the opposite effect and spreading off
the suggestion that cathode keying would be better and the frequency in use causes annoying interference to
would automatically put a negative potential on the many others. They can and should be avoided.
grid when the key was opened, thus to ensure rapid cut-
off and minimum sparking. But that was as far as he Curing Key Clicks
The cure is to slow up the rate of signal rise -and -fall
to produce a keyed waveform as in Fig. 5. At hand
HT+ keying speeds the time taken during build up and decay
is a small proportion of the total time of even a dot; the
intelligibility of the signal is therefore not impaired.
This can begin to become a problem with high speed
auto -keying and a compromise is necessary, but not in
amateur CW working.
Cathode keying is the simplest effective method of
keying but it has disadvantages. To minimise generation
of parasitics RF input and output circuits must avoid
long leads. The cathode is common to both and should
therefore be grounded to RF as directly as possible. If
the cathode is keyed this grounding must be by use of a
by-pass capacitor which should be rated for full plate
voltage of the keyed valve and have sturdy short con-
nections from capacitor plates to cathode and earth.
Minimum value -01 µF, preferably -05
With cathode keying the rise and decay time can be
slowed down by use of an LF choke and fairly large
capacitor. Choke values between 1 and 5 Hy. and
Note Thick line indicates capacitor 0.5 to 2.0 /IF are best found by trial and error.
RF circuit which At " break " the capacitor will charge, and then at the
must be kept short
Bias and robust. next " make " discharge with a spark at the key. This
can be minimised by insertion of up to 100 ohms resist-
'Fig.1 Cathode keyed amplifier ance in series with the capacitor. The RF chokes andVolume XXVIII THE SHORT WAVE MAGAZINE 271
001 ILF capacitor at the key position in Fig. 6 do not
affect the transmitted signal and serve only to prevent
the remaining small spark at the key from affecting other
receivers in the immediate vicinity.
The combination of choke and capacity can be ad-
justed to give a satisfactory shape to the keyed waveform
but adjustments are interlocked and valid for only one
value of keyed current and circuit conditions.
Valve Keyer
If cathode keying is preferred the better way is to use
Thick line indicates RF circuit which must be kept short
a valve keyer, as in Fig. 7. In this case no LF chokes are
required, the time constant of rise and fall being deter- Fig. 6. Click eliminator for cathode keying
mined by the R/C values in the grid circuit of the keyer
valve and these values can readily be made variable.
The key is required to handle negligble current, it is not
necessary to use a relay and the keyer can easily be
adapted for use with an electronic keying system. The
Fig.2 Keyed signal envelope for Fig.1 as It should be.
one disadvantage is that there will be an appreciable
voltage drop crosss the keyer valve. This is acceptable
in the early stages of a transmitter but becomes more of
a problem as one nears the final amplifier and power
levels rise.
Blocked Grid Keying
There are various other alternatives which avoid the
power loss of a valve keyer but retain convenient adjust-
Fig.3 Keyed signal envelope for Fig.4 as it probably is. ment of rise and fall. The one preferred by the writer is
blocked grid keying of a driver stage, shown in Fig. 8,
Pickup wire
p.272. Here sufficient negative bias is applied to the grid
of the keyed valve to give complete cut-off when the key
is up. When the key is down the negative bias is reduced
to the proper working value. Rise and fall constants
can be varied by adjustment of R and C values.
With this system and any other involving variation
of bias do not overdo the amount of bias needed for cut-
off. For example, in the valve keyer and blocked grid
cases if -200v. is the required cut-off value, use -220v.,
Slow running
but no more. With much higher bias values it becomes
time base more difficult to adjust R and C and enhanced ratings
are required for them.
Fig.4 Using oscilloscope to check keyed signal.
So far we have considered the shaping of a keyed
signal at the keyed stage. It is generally preferable to
-250 V PA Cathode
470K 2M 4701(
la) Keyed signal envelope correctly shaped.
(b) Probable actual signal envelope obtained
using click eliminator.
Fig.5 Corrected keyed signal envelopes which will
avoid key clicks in receiver. Fig.7 Valve keyer272 THE SHORT WAVE MAGAZINE July, 1970
ELECTRONIC MORSE CODE
To soften 'Make' increase C
To sof ten'Break' increase R GENERATORS
FLIP-FLOP CIRCUITS AND DECODE
Thick line indicates
RF circuit
DIVIDERS
Part II
G. E. GOODWIN (G3MNQ)
-05 to-5pF The first part of this article appeared in our
RFC issue for June. For continuity, it should be
read with what follows. Further parts on the
.001pF 50K same theme will appear in succeeding issues.
Key
-Editor.
10K
TAKING up from where we left off, with Fig. 15 on
p.221 of the June issue of the Magazine, it must now
Blocking bias ye --,AAN be explained that in relatively simple JK flip-flops there
50K
will be three trigger inputs, two DC inputs, two outputs
Fig.8. Blocked Grid keying and two power supply leads. A train of pulses can be fed
into one of the trigger inputs, known as the " clock
input," and each pulse will change the state of the
arrange keying in a transmitter so that there is at least outputs, i.e., the one that was positive will fall to zero and
one buffer stage between oscillator or frequency control that which was zero will rise to the positive supply
potential. When considering only one of the outputs this
and the keyed stage, but otherwise as early as possible
and at low power. If following stages are linear-Class-A, will go positive once for every twice the clock input
AB or B-the signal envelope should be faithfully goes positive-in other words the circuit is dividing the
reproduced right through to the final amplifier. However, clock input by two (two inputs for one output). This
if the keyed stage is followed by frequency doubling and/ can be very useful in circuits which " count " pulses as
or Class -C amplifier stages much of the good work done any number of flip-flops can be put in series to divide the
in the keyed stage will be lost. For transmitters with input by any number which is a power of two. The other
Class -C amplifiers it is therefore better to position the two trigger inputs, one known as " J " and the other as
keyed stage as near the final output as possible, the " K," can be applied to control the operation of the
penultimate stage being the best compromise in the clock input so that under some conditions it has no
average amateur transmitter. In this case it may be found effect. This can be used when it is required to divide
necessary to " overdo " correction in the keyed stage to by a number which is not a power of two, say 10, for
achieve a satisfactory keyed envelope from the Class -C
amplifier.
+4 +8
Other Considerations
Nothing has been said so far about other factors which Input- T T T
Q Q Q +16
can affect bad shaping of a keyed signal, largely because
they do not have such a serious effect at the receive end.
Nevertheless, one must record that supplies to the keyed Fig.16
stages should all have good regulation. Bias and low
voltage PSU's should preferably be regulated. High -
voltage supplies should use choke input filters and large
output capacitors. No stage should be overdriven; this Q LJ J Q
Input
latter factor adds difficulties in adjusting keying con- 2 3 4
stants, quite apart from other ills. Q_T Output
Frequency Stability
I
Decade reset (Inc
One could say much about frequency stability but Fig.47
perhaps it is sufficient to record that an amateur trans-
mission must have short-term stability at operating
frequency, involving a drift of not more than 50 Hz in
30 minutes, the drift spread evenly over the period. This
Fig. 16. Four flip-flops in series to produce divide -by 2, 4, 8
is a minimum for SSB working and is a reasonable or 16. Fig. 17. Four flip-flops with feed -back to give a divide -
requirement for CW. by -10 result.Volume XXVIII THE SHORT WAVE MAGAZINE 273
instance. The two DC inputs are usually called " S " Set
and " C " (for " set " and " clear ") and potentials
applied to these inputs will over -ride any of the J, K s
or clock inputs, and will hold the flip-flop in one parti- Input
cular state until it is removed. These inputs can be BS1
Q
852
used to put a number of flip-flops into a particular state Ir
prior to commencing a count. They are normally held
positive and made zero to operate the flip-flop.
Since the flip-flop has two stable states which can T Output AND
be determined simply by the application of a small 1
pulse, it is sometimes called a " memory " as it will
retain indefinitely the state into which it has been put. '2' Output AND
By this means it is possible to initiate manually a function 2
in the programmer; the flip-flop would remember that
initiation and action could be taken on it at the correct '3' Output AND
time. 3
The two outputs are usually called " Q " and " (5,"
Q being positive when the C input is made zero instead '4' Output AND
4
of being held positive, while Q is made positive if S is
made zero. Fig.18
The proper symbol for the flip-flop is shown in Fig.
15 (see p.221, June) where " T " is the clock input.
Fig. 18. Two flip-flops dividing by four with AND -gate
Dividers decoders.
Since one flip-flop can be used as a divide -by -two,
it follows that if two are connected in series then a remain at zero. This is achieved by using four AND
divide -by -Our can be produced. Similarly, three in gates connected as shown in Fig. 18, BS1 and 2 being
series will divide by 8, etc., and this can be achieved by the divide -by -four with AND gates 1-4 forming the
connecting the Q output of one to the T input of the next decoder.
-see Fig. 16. The flip-flops are set into their initial state by the
Two flip-flops in series will have four outputs (Q application of a pulse to the S input; then, AND1 will
and Q from each) two of which will be positive and the have its output positive. The first pulse applied to T
other two zero at any given time. To make use of these will move the flip-flops into their second state, AND2
four discrete states of the divide -by -four these outputs having the positive output. Similarly, the second and
must be " decoded " from binary into decimal code, third pulses will produce positive outputs from AND3
i.e., one output positive for each state while the others [coned. p. 27S
To Selection Matrix
O 3 4 5 9
0 0
-9V -9V -9V -9V -9V -9V -9V -9V -9V
VVVV.- M/ W- NVV\r"-- -tAAAr.- .VVVv-^ VVVV..- 0VVVV4-9v All 22K
2N 29 26
ci*
-..-VVV\r --VVV\r ---/VVr -osAAA.r All 33K
m Et Et it izz
mememisimeikamminuimemmen Q4
illIONIUDINO1111111IMPUMEMIEDM Q3
111MIDAIMMDIIIM11111111MOIONM p 3
Q2
Q2
11=11111111111111111EMNIIIMENIMMII
fig. 19
Fig. 19. Decade decoders with emitter followers.You can also read
